The sharing of imaging devices across computer networks is a common arrangement. Network imaging devices by way of example and not limitation, include network printers, network scanners, network faxes and other such network devices for conveying electronic information between a computing system and a user. Although this discussion will focus on printers and the printing infrastructure, the same information is applicable to other network imaging devices.
Printers are usually very tightly coupled with an individual PC or server and thereby tend to create delays and unavailability problems for users, particularly in situations where the server is down or overloaded, or where the printer is malfunctioning. The tight coupling of printers also necessitate extensive reconfiguration of a PC when there is a need to change print servers or printers. Furthermore, it is not uncommon within current printing schemes that a particular printer will become overloaded thus delaying print jobs, while another printer remains idle.
Current methods employed to overcome some of the problems discussed above include providing standby printers that only serve the purpose of being available as a swap-in in the event the active printer should fail. This same method is also employed with print servers. In other words, an identical piece of computing hardware is configured and placed on standby ready to be swapped in as needed. Apart from the obvious issue of the cost involved in equipment duplication, there are several other problems with this approach. For example, in the case of a standby server, logistical problems and extra work are created particularly from an administrative standpoint, because it is necessary to ensure that any changes, upgrades or reconfigurations that are applied to the functional server are also applied to the standby server. Another problem that arises from equipment duplication is the under-utilization of physical resources; a phenomenon that stems from having equipment that is just sitting around. Yet another problem is related to the loss of transient data information that occurs when switching out physical equipment. For instance, current print jobs or fax requests of particular documents that have been loaded onto a server are lost when that equipment is substituted with another one. In other words, the swapping of equipment does not provide any means for salvaging any imaging jobs that have been sent to the server at the time of the equipment failure or equipment unavailability. This should not be confused with fault tolerance with respect to jobs. If a job is in the middle of printing that job cannot be recovered.
Accordingly, there exists a need for providing a distributed environment in which printing and other imaging services are more efficient and reliable. The present invention provides a system that relieves the user from the tasks of searching for network printers and/or manually moving jobs to available print queues. There also exists a need to provide a system with fail-over, built in monitoring and load balancing capabilities that ensure that printing services are always available. Furthermore, there exists a need to simplify the administration of network printing devices and print servers. There is also a further need to provide location and name transparency of network printer servers, from the end users perspective.